<!DOCTYPE html>
<html class="reftest-wait">
<head>
    <title>Finishing a View Transition on a scrolled page should properly reset state</title>
    <link rel="author" title="Tim Nguyen" href="https://github.com/nt1m">
    <link rel="help" href="https://drafts.csswg.org/css-view-transitions-1/">
    <link rel="match" href="reset-state-after-scrolled-view-transition-ref.html">
    <style>
        html {
            background: lightblue;
        }
        body {
            background-color: lightgreen;
        }
        ::view-transition-group(*) {
            animation-duration: 2s;
        }
    </style>
</head>
<body>
    <p>Start</p>
    <div id="block" style="height: 150vh"></div>
    <p>End</p>

    <script>
        function scrollBy(y) {
            return new Promise(resolve => {
                addEventListener("scroll", () => {
                    requestAnimationFrame(() => {
                        requestAnimationFrame(resolve);
                    });
                }, { once: true, capture: true });
                document.documentElement.scrollBy({
                    top: y,
                    behavior: "instant"
                });
            });
        }
        addEventListener("load", async () => {
            await scrollBy(document.documentElement.scrollHeight / 2);
            const transition = document.startViewTransition(() => { block.style.height = '200vh' });
            await transition.ready;
            scrollBy(document.documentElement.scrollHeight / 2);
            await transition.finished;
            document.documentElement.classList.remove("reftest-wait");
        });
    </script>
</body>
</html>
